The possibility of organic modification of montmorillonite (MMT) in hydrocarbon solvents by employing ionic liquid-type surfactants was investigated. As a first example, 1-methyl-3-tetradecylimidazolium chloride ([C(14)mim]+CI-) was used to treat pristine MMT in xylene. The dispersion of MMT in xylene was significantly improved, the collected organifically modified MMT displayed a sufficiently enlarged interlayer spacing. The novel art of MMT organic modification is specifically advantageous to the preparation of polyolefin-based nanocomposites. A polypropylene/MMT nanocomposite was exemplarily prepared by directly dissolving polypropylene in the MMT modification system and found to possess an excellent thermal stability. (c) 2006 Wiley Periodicals, Inc.